Q:
I've got about 50 boxwoods planted all around my house, and I'm starting to get
worried about that new boxwood blight I've been hearing about. How much of a
threat is it in Cumberland County? Should I start spraying next year?

A:
Well, I hate to tell you, but Cumberland County is one of the first places in
Pennsylvania where this new blight – caused by the fungus Cylindrocladium pseudonaviculatum – has been confirmed.

A
landscape specimen tested positive for it this past May. It's also been
confirmed in Lancaster County.

First, forget spraying. None of the
fungicides labeled for home use have tested as being useful against this
disease.

Second, although boxwood blight is very
capable of killing boxwoods, it hasn't been spreading by storm – at least not
yet. It's definitely worth watching, but it doesn't mean your boxwoods are
doomed.

Penn State Extension offers some advice on
what you can do to keep existing boxwoods healthy:

1.)
Check them for symptoms. The first sign is usually brown spots on the
leaves, often with dark borders. The leaves then turn light brown all over and
drop – usually fairly quickly over a few weeks. Inspect the stems because they
usually develop dark "cankers" (i.e. lesions or small wounded spots).

2.)
Check any new boxwoods carefully and avoid planting new ones among existing
ones. You could bring infected plants into the garden – possibly even before they
show symptoms. Some are even suggesting not buying boxwoods until we see how
this shakes out.

3.)
Keep the plant foliage as dry as possible, i.e. by not letting plantings
get so big and dense that they grow together and by not watering over the foliage.
Thinning out excess dense growth in spring also improves air circulation and
helps dry the leaves better. This fungus thrives in damp, humid and warm
conditions.